Rib hole-detector for revolving and stationary head rib knitting machines



Oct. 19, 1954 E. vossEN RIB HOLE-DETECTOR FOR REVOLVING AND STATIONARYHEAD RIB KNITTING MACHINES 3 Sheets-Sheet 1 Filed Aug. 22, 1952 ll lllbhl nulmlm N. m5 m A TIDE/V5) Oct. 19, 1954 v E. VOSSEN RIBHOLE-DETECTOR FOR REVOLVING AND STATIONARY HEAD RIB KNITTING MACHINES I3 Sheets-Sheet 2 Filed Aug. 22, 1952 HOV TRANSFORMER 2 3 /3 R E L L l\ OR T N 0 c INVENTOR fDW/MD V0551 ATT NEY Oct. 19, 1954 E. VOSSEN2,691,880

RIB HOLE-DETECTOR FOR REVOLVING AND STATIONARY HEAD RIB KNITTINGMACHINES Filed Aug. 22, 1952 :s Shee ts-Sheet 3 I |l256 M 252 fHWflED.VOSSEN.

Patented Oct. 19, 1954 UNITED STATES PATENT OFFICE RIB HOLE-DETECTOR FORREVOLVING AND STATIONARY HEAD RIB KNITTING MA- CHINES 14 Claims. -1

This invention relates to a rib hole-detector for revolving andstationary head rib knitting machines. It also relates to thestop-motion devices which are associated with said hole-detector andwhich said hole-detector actuates in order to stop said rib knittingmachines upon the detection of a hole or similar defect in the knittedfabric.

The rib hole-detector which is herein described and claimed isapplicable to three kinds of rib knitting machines. One of theseknitting machines is provided with a revolving head. In this machine theknitted fabric is stationary in the sense that it does not revolve. Thesecond machine is provided with a stationary head and here, of course,the knitted fabric does revolve. This machine has no take-up arms. Thethird machine is also provided with a stationary head but in addition itis equipped with vertical revolving take-up arms. In this machine theknitted fabric revolves with the revolving takeup arms. All threemachines may be grouped under the broad heading or classification ofcircular knitting machines.

The rib hole-detector which comprises the present invention isuniversally adaptable to all three knitting machines above described.When it is installed in the stationary head rib knitting machines wherethe knitted fabric revolves, it is held in a stationary position. Whenit is installed in the revolving head rib knitting machine where theknitted fabric is stationary, it is made to revolve with the revolvinghead and relative to the knitted fabric. In all cases, the ribholedetector is mounted within the knitted fabric tube and its action isdirected radially outwardly.

The rib hole-detector herein claimed may also be made to operate fromthe outside of the knitted fabric tube radially inwardly, if this shouldbe desired. This would particularly be true where the knitted fabricrevolves and in such case the rib hole-detector would be mountedstationary on the outside of the knitted tube.

More specifically, the rib hole-detector which comprises this inventionincludes two basic elements: The first is a double ring frame whichengages the knitted fabric to spread it taut for the hole detectionprocess. The second is a holedetector assembly which includes aplurality of probes or feelers which engage the knitted fabric in thearea which is spread taut by the double ring frame. In some cases, thedouble ring frame and the hole-detector assembly are mounted together,the latter being supported by the former. In other cases, the doublering frame may be mounted within the knitted tube and the hole-detectorassembly may be mounted outside of the tube. When the hole-detectorassembly is mounted within the tube, its probes or feelers pressradially outwardly against the taut area of the tube. Where thehole-detector assembly is mounted on the outside of the knitted tube,its probes or feelers press radially inwardly against said taut area.

In all cases an electric switch mechanism is provided for stopping theknitting machine when a hole or similar defect is encountered anddetected by one of the probes or feelers of the rib hole-detector. Thisswitch mechanism is mounted on the outside of the knitted tube. Hence,it may be incorporated into the rib hole-detector when said detector ismounted outside said knitted tube but it must constitute a completelyseparate and independent device when the rib hole-detector is mountedwithin the knitted tube.

In the latter case it is necessary to provide an actuating mechanismbetween the rib hole-detector on the inside of the knitted tube and theswitch mechanism on the outside thereof. This actuating mechanismcomprises two elements: one is mounted within the tube and the other ismounted outside of the tube. The inner element is actuated by thehole-detector. The outer element is actuated by the inner element. Theswitch mechanism is actuated by the outer element. Thus a chain reactionis set up when a hole or flaw is detected in the fabric, beginningwithin the knitted tube, permeating or passing through the wall of saidtube, and ending outside of the tube. The inner element includes abumper or plunger which is normally in retracted position. It is alwaysunder the influence of a spring, however, which tends to urge itradially outwardly and into engagement with the taut area of the knittedtube. A trigger mechanism is also included which releases said bumper orplunger when a hole or other flaw is detected in the knitted tube. Uponthe happening of this occurrence, the bumper or plunger shoots radiallyoutwardly against the knitted tube, distorting or stretching itsufiiciently to enable said bumper or plunger to project beyond thedouble ring frame. In this position, the bumper or plunger encounters anoutside arm or the like which constitutes the outside element abovementioned and dislodges it from its normal or inoperative position. Thishas the effect of actuating the switch mechanism and stopping themachine.

Where the switch mechanism and the hole-detector are mounted together ina single assembly, there is no need for an actuating mechanism of thetype last above described. Instead, the holedetector acts directly uponthe switch mechanism immediately and automatically upon the detection ofa hole or other flaw in the knitted material.

In both cases last mentioned, that is, in the case of the switchmechanism and the hole-detector being mounted together to form a singleassembly and in the case of the hole-detector being mounted within theknitted tube and the switch mechanism being mounted outside of theknitted tube, r e-setting means is provided in order to start theknitting machine and to reactivate the hole-detecting mechanism. In thecase of the hole-detector and switch mechanism being incorporated into asingle assembly, a manually operated handle is provided which isconnected both to the hole-detector and to the switch mechanism. Allthat need be done to reset said hole-detector and said switch mechanismis to pull upon the handle. This can very readily be done since in suchase, the hole-detector and switch mechanism assembly are located outsideof the knitted tube within convenient reach of the operator of themachine. In the other case, the bumper or plunger may be engaged fromthe outside of the knitted tube in order to reset the hole-detectorwhich is located within the tube. This is very simply done by merelypressing upon said bumper or plunger until it regains its .retractedposition. Similarly, the arm on the outside of the knitted tube whichthe bumper or plunger engages through the knitted material when a holeis encountered is simply swung hack to its normal position where it maybe engaged by said bumper or plunger. This has the effect of re-settingthe switch mechanism which in this case .is also located outside of theknitted tube.

The rib hole-detector herein described and claimed aifords manyimportant advantages and possesses many important features. Among theseadvantages and features may be listed the following:

1. The double ring frame which engages the knitted material and holds itin proper position and in proper condition for the hole-detectingprocess is an extremely important element. In the first place, it takesthe place of the conventional spreader rings which are today employedfor the same purpose. These spreader rings are made in various sizes tofit the various sizes of knitted tubes. Each tube requires .a spreaderring of corresponding size and a spreader ring made for any one size ofknitted tube cannot be used for any other size of knitted tube. In thepresent invention, on the other hand, a single size double ring framemay be employed in connection with knitted tubes of every conventionaldiameter. It should of course be small enough to enter the smallest tubeand this is the only prerequisite to its universal use. If it fits thesmallest tube, it will fit all of the larger tubes.

It is not essential that the double ring frame be .concentric with theknitted tube. It suflices that the curvature of .the double ring frameapproximate the curvature of the knitted tube. An important aspect ofthis double ring frame is its adjustability relative to the tubularmaterial. It;

may be shifted toward or away from the knitted tube in order tocompensate for the various sizes of knitted tube which may beencountered.

2. The adjustable feature of the double ring condition. In other words,the knitted material which at "any particular moment -is disposedbetween the two rings of the frame constitutes a relatively wide belt orzone which is maintained by said rings in taut condition. A taut zone orbelt of this character cannot be achieved by the single spreader ringsof the prior art.

4. A further advantage resides in the fact that the two rings of thedouble ring frame are offset from each other to conform to the taper ofthe knitted tube. It is well known that the knitted tubes which circularknitting machines produce are not perfectly cylindrical in shape.Instead, they taper inwardly from relatively large proportions at theirupper end to relatively small proportions at their lower end. It is thistaper to which the double ring frame of the present invention conforms.

5. Still another important feature is the vertical bar which links thetwo rings immediately adjacent the series :of probes or feelers whichsaid double ring frame supports. This vertical bar precisely positionsthe taut belt of the knitted material relative to the probes or feelers.Said vertical bar is inclined to correspond to the .taper of the knittedtube, just as.

the two rings of the double ring frame are offset for the same purpose.The vertical bar cooperates with the two rings of said frame to hold theknitted material so precisely in place that it is possible to set theprobes or feelers most accurately and sensitively relative to saidknitted material. This is essential to the precise functioning of theapparatus herein claimed. The vertical bar also serves another purpose:it helps prevent the knitted material from being pushed inwardly beyondthe range of its normal stretch or elasticity when the bumper or plungerabove mentioned is returned to its retracted inoperative position.

6. An important advantage of the double ring frame is the double bearingwhich the two rings provide for the hole detecting mechanism, both whenthe mechanism is stationary and when it is in motion. The double bearingrenders it .possible to set the hole detecting mechanism very preciselyrelative to the knitted material and the double bearing will maintainsuch precise setting or adjustment indefinitely.

7. The switch mechanism in the present device also provides importantadvantages over the prior art. It performs two functions: in the firstplace, it acts as a switch to stop the machine as soon as a hole orother similar defect is detected. In the second place, it serves as acutoff switch which disconnects. the unit from the knock-off controller.This is important because .the hole detecting mechanism would otherwisekeep on knocking 01f the machine when the fabric is found to be faultyover a relatively large area, whereas this feature enables the operatorof the machine to render the hole detecting mechanism inoperative untilthe fabric runs whole again.

frame is important for an entirely different pur- Once the fabric runsclear of defects, the switch mechanism may be re-set to its normalposition, ready to detect other defects in the fabric.

Preferred forms of this invention are shown in the accompanying drawingin which:

Fig. '1 is a vertical section through a revolving head rib knittingmachine and the knitted tube which it produces, showing a rib-holedetector made in accordance with one form of this invention, saidhole-detector being mounted within the knitted tube for revolvingmovement with the head of said knitting machine.

Fig. 2 is a fragmentary top view thereof.

Fig. 3 is a view similar to that of Fig. 2 but showing one of the probesor feelers caught in a hole in the knitted fabric and showing the bumperor plunger in forwardly projecting position as a result thereof.

Fig. 4 is an enlarged view of the hole detecting mechanism following itsdetection of a hole and showing the bumper or plunger in its forwardlyprojecting position in engagement with the knitted fabric.

Fig. 5 is a fragmentary enlarged front view of said hole detector.

Fig. 6 is a fragmentary vertical section showing the hole detectingmechanism within the knitted tube and the switch mechanism outside ofthe knitted tube which is actuated by the hole detecting mechanism whena hole is detected in the fabric.

Fig. 6A is a fragmentary top view of the mechanism shown in Fig. 6, butshowing that the bumper or plunger may be disposed on the opposite sideof the hole detector from the side which it occupies in the precedingfigures of the drawing, said view being taken on the line 6A-6A of Fig.6.

Fig. 6B is a sectional view showing the hollow spindle or shaft ofanother type of knitting machine having a revolving head and showing aswitch mechanism mounted within the knitted tube and connected to thestop motion mechanism by means of a conductor which extends through saidhollow spindle or shaft.

Fig. '7 is a top view of a hole detector made in accordance with asecond form of this invention, showing it in engagement with the outsideof a knitted tube which is produced by a stationary head rib knittingmachine.

Fig. 8 is an enlarged front end view of said hole detector, looking inthe direction of arrows 8, 8 of Fig '7.

Fig. 9 is an enlarged side view of said hole detector, showing theswitch mechanism theron.

Fig. 10 is a view similar to that of Fig. 9 but showing the switchmechanism in closed position.

Fig. 11 is a wiring diagram showing the electric circuit of the holedetecting mechanism herein claimed.

Fig. 12 is an enlarged sectional View showing a modified form of doublering guides.

Referring now to the first form of this invention as shown in Figs. 1 to5 inclusive it will be seen that a conventional revolving head circularknitting machine 10 is provided. The knitted tube [2 which is made onsaid machine is stationary in the sense that it does not revolve. Withinsaid tube is a vertically extending shaft M which is connected to therevolving head of the machine and which rotates therewith on its ownlongitudinal axis.

Secured to shaft 14 is a bracket l6 having arms I8. It will be notedthat these arms support the double ring frame 20 and the latter, inturn, carries hole-detector 22 for engagement with the knitted tube l 2.Double ring frame 20 comprises an upper ring member 2A and a lower ringmember 26 which are connected at their respective end portions to blocks28 and 30 and a pair of rods 32 and 33 which are secured to said blocks28 and 30 by means of set screws 34. It will be seen that these rods 32are in spaced parallel relation to each other and that they occupy acommon horizontal plane. They are slidably mounted in blocks 36 of armsl8 of the bracket and set screws 38 are provided for securing said rodsto said blocks. It is by means of set screws 38 that rods 32 may beadjustably positioned on bracket I6 relative to vertical shaft I 4 andrelative to the knitted tube I2. It is by this means that the doublering frame may be shifted into proper position relative to knitted tubesof various proportions. It is also by this means that the double ringframe may be made to apply greater or lesser pressure upon the knittedtube.

Ring members 2:3 and 26 may be cast integrally with blocks 28 and 30 andhence integrally with each other. If desired, they may be secured byconventional fastening means and methods to said blocks and in such casethey would, of course, be separate and independent elements, either castor machined, as desired. But whether they are cast together or fastenedtogether ring members 24 and 26 are maintained in spaced parallelrelationship and occupy spaced horizontal planes which are situatedabove and below the common plane which rods 32 occupy. The leading edgesof the two ring members are arcuate in shape as Figs. 2 and 3 clearlyshow. It will be seen that the two ring members are offset from eachother, the upper ring member projecting slightly beyond the lower ringmember. These two ring members are offset to the same extent that theknitted tube I2 is tapered. See Fig. 1. Hence, the two ring members willexert a substantially equal force or pressure against the knitted tube.

Secured to the two ring members 24 and 26 is a vertically extending barid which has horizontally extending arms &2 and M respectively. Thesearms abut the facing sides of the two'ring members and they are securedto said ring members by means of screws 46 or any other suitablefastening means. Vertical bar it is positioned centrally of the two ringmembers and its outer face is substantially fiush with the curved edgesof said ring members. Consequently, vertical bar 4!? is inclined in thesame measure that the ring members are offset and to the same extentthat the knitted tube i2 tapers.

It will be seen in the drawing that the curved ed es of ring members 2 3and 26 are normally in engagement with the inner surface of knitted tubeI2 and this is also true of the vertical bar 40. The knitted fabric isheld relatively taut between the two ring members so that any holes orother defects of like nature which may happen to be formed therein willvery readily be detected by the hole-detecting mechanism which willhereinafter be more fully described.

Hole-detector 22 is mounted between the two ring members 24 and 26 asFig. 4 clearly shows. The ring detector is thereby supported both on topand on the bottom and it is thereby provided with a very secure andrigid anchorage. This is extremely important for the proper functioningof the device and particularly when it reacts to the detection of a holein the knitted fabric. More specifically, hole-detector 22 includes acasing 48 which has a top wall 58, a bottom wall 52, and one side wall54. The other side of said casing is open. The top and bottom walls ofthe casing are secured to the upper and lower rin members by means ofscrews 56. It is this casing which supports the moving parts of thehole-detecting mechanism.

Slots 58 are formed in the top and bottom walls of the casing and itwill be understood that these slots are in registration with each otherand extend longitudinally of the casing. A pin 69 projects through theseslots and mounted on said :aeeigsso pin, between the upperand lowerwalls of the casing, is a block 62. Pin 60 serves as a pivot or pintlefor said block 62, enabling the block to pivot into and out of thecasing. See Fig. 3. It will also :be noted that the two outwardlyprojecting ends of pin to are engaged by tension springs 6'4 and thatthe opposite ends of said springs are anchored to the top and bottomwalls of the easing by means of rivets 66. These springs tend to pullpin 69 in the direction of the ring members 24 and 2E, leftwardly, asviewed in Figs. 2 and 3. The reason for this will shortly becomeapparent.

Block "52 has a plurality of spaced parallel holes 88 "formed thereinand occupying said holes are tubular members it. These tubular membersare closed at both ends, their closed forward ends being shown in Fig. 5of the drawing. Slots 72 are provided in the front closed ends of tubes'19 and probes or feelers it are slidably mounted in said tubes withtheir front ends projecting through said slots. The end portions of saidprobes or feelers are reduced for ready penetration into any holes orsimilar flaws which may be encountered in the knitted fabric. Withintubes it are springs (not shown) which act upon the probes or feelersand urge them resiliently forwardly. It is these springs which maintainthe probes or feelers in tensioned engagement with the knitted fabric.

It will be seen that a pair of projections or bosses T8 are provided onthe forward end of block 62. It will also be seen that a pair of catchmembers 822 are formed at the corresponding end of casing 48. When block62 is swung into position within casing 48, catch members as engagebosses 18 and tend to prevent said block from swinging outwardly fromsaid casing. The bosses are held in tensioned engagement with said catchmembers by means of springs 54 which act upon block -52 through pin 66.

Arrow 82 in Fig. 2 indicates the direction of movement of the entireassembly mounted on shaft 14, more specifically, bracket it, double ringframe 2t and hole-detector 22. As this entire assembly revolves aboutthe axis of shaft I4, probes or feelers ill scan the knitted tube andwhen a hole 234 is encountered in said tube, the probe or feeler whichencounters it will enter said hole as Fig. 3 clearly shows. Since thehole is formed in a stationary tube, further movement of the assemblylast mentioned will produce the eiiect also shown in Fig. 3 of block E2swinging out of casing 18. This is the first step in the stop-motionchain of events which leads to the stopping of the knitting machine.

Secured to block 52 is a bar 86 which serves as a trigger with respectto a bumper or plunger 83. Bumper or plunger 58 is a J-shaped memberhaving a longitudinal portion es and an arcuate end portion 52. At theproper time, that is when a hole is detected in the knitted fabric, thisbumper or plunger thrusts forwardly into engagement with said fabric asFigs. 3 and 4 clearly show. The eifect of this action will shortlyappear.

A block 94 is secured by means of screws 95 to casing #28 and it will benoted that said block has a channel formed therein to accommodate thelongitudinal portion 96 of the bumper or plunger 88. Said longitudinalportion at is slidably movable through said channel in block 94 so thatthe bumper or plunger may move from its retracted position in Fig. l toits projected position in Fig. 4 and back again to its Fig. 1 position.A crossbar $3 is secured to the back end of longitudinal portion til Ofthe bumper or plunger and a pair of coil springs Hit are secured at oneend V bracket 52b.

8 to said crossbar and at the opposite end to screws Hi2 on block M.Thus it is, that the plunger or bumper is urged by said springs to itsprojected position shown in Fig, 4 and when said plunger or bumper isreturned to its retracted position as shown in Fig. 1, this movementtakes place against the action of springs it!!! and it has the eifect-ofloading said springs.

It has been said that bar '86 serves as a trigger which releases thebumper or plunger from its retracted position and enables it to moveforwardly under the influence of springs [09. Bar engages a second barI0 through a slot I06 in casing 48. Bar m4 is pivotably secured to block94 and a leaf spring Hi8 engages said pivoted bar we to hold it inengagement with bar 86 on block 82. A plate i it is fastened to block 94by means of screws l l2 and it will be seen that said plate secures theleaf spring N38 to said block 54 and holds said left spring inengagement with bar me.

It will be seen in Fig. 3 that a shoulder lid is provided on bar lot.When the bumper or plunger is in its retracted position, shoulder H4engages crossbar ii and prevents the bumper or plunger from movingforwardly under the action of springs liiil. When block 62 is caused topivot to its Fig. 3 position, when a hole or other defect of like natureis encountered in the knitted fabric, bar 8"5 cams pivoted bar Hidoutwardly until crossbar 98 clears shoulder H4. The bumper or plunger isnow free to thrust forwardly under the action of springs Hit to its Fig.4 position in engagement with the knitted fabric.

When it is desired to reset the mechanism last above described, thebumper or plunger is pushed backwardly, through the knitted fabric,until its back end encounters bar 86. Further backward movement of thebumper or plunger causes block 6-2 to pivot backwardly from its Fig. 3position to its Fig. 2 position. Not only is block 62 caused to pivot asaforementioned, but it is also caused to slide backwardly a sunicientdistance to enable its bosses 8 to clear the clips Bil of the casing. Atthe same time, pivoted bar EM is rendered free to swing back from itsFig. 3 position to its Fig. 2 position and its shoulder H4 re-engagescrossbar 98 to hold the bumper or plunger in retracted position.

It will be noted that all of the above action takes piace between thetwo ring members 2t and 26 of the double ring frame. All of the pivotedparts above described are provided with double bearings, that is, with abearing support on each side thereof. Not only is this true of thepivotedparts but it is also true of the casing 53 which supports them,the upper wall of said casing being secured to ring 2 3 and the lowerwall to ring 26.

Th next step in the chain of events which stops the knitting machinetakes place outside of t e knitted tube. See Fig. 6. It will be notedthat the bumper or plunger 88 causes a bulge i it (Fig. 4) to form inthe knitted fabric, beyond vertical bar it and beyond the curved edgesof ring members 2d and 28. The bumper or plunger is now in a positionwhere it is able to encounter a pivoted arm 518 which is supported by aA set screw i221) in said bracket engages said arm H8 and it is themeans by which said arm may be adjustably positioned in said bracket.Bracket $26 is adjustably secured to a shaft 22 which is rotatablysupported by a second bracket iZd. Said second bracket is mounted on aframe member 126 of the knitting machine. A collar I28 above bracket I24and a second collar :30 below said bracket are socured to shaft I22 toprevent axial shiftin or dislodgement thereof. When the bumper orplunger 88 strikes arm IIB through the bulge in the knitted tube, saidarm is caused to swing from one position to another and thereby shaftI22 is also caused to turn on its longitudinal axis a correspondingangular distance.

A recess or depression I32 is formed in shaft I22 to accommodate a ballI3 2. This ball is mounted in a hole I36 formed in bracket I2 5. Acompression spring I38 in said hole bears against ball I34 and holds itin tensioned engagement with shaft I22. A screw threaded plug I46retains said spring in said hole. It will be understood that when ball I34 is in recess I32, shaft I22 will be tensionally held in its operativeposition shown in Fig. 6, ready for engagement with bumper Or plunger38. A positive force is required to dislodge said ball from said recessand thereby to free the shaft and arm I I6 for angular movement. Thisforce is provided by the bumper or plunger. A diametrically oppositerecess I22 is also provided in shaft I22 so that when said shaft and itsarm I I8 are turned a full 180, ball I34 will enter said diametricallyopposite recess I42 and said shaft and said arm will once again beresiliently locked in position and they will remain in such positionuntil dislodged therefrom by a positive force. In this case, the forcewill be manually effected and directed and said shaft and its arm willthereby be returned to their Fig. 6 positions.

The top end of shaft I22, designated in the drawing as I22a, is reducedin size and cut down to the shape of a flat bar. Fiber insulation N14 isprovided on both sides of said fiat end portion I22a to serve aselectrical insulation. It will be noted in Figs. 6 and 611 that a fiberor plastic tube I26 is disposed in a vertical hole M8 in bracket I24. Arod I56 is rotatably mounted in said fiber or plastic tube and its upperend I52a s also reduced and cut away to the shape of a flat bar. A pairof brass or copper leaves I52 is secured at one end to flat portionI501]. of rod I56 and the opposite ends of said leaves abut fiberinsulation I l i. When arm II8 and shaft I22 are in their Fig. 6 and 6apositions, fiber insulation M4 will prevent leaves I52 from makingelectrical contact with fiat end portion I22a of shaft I22.

When a defect is encountered in the knitted fabric, one of the probes orfeelers will be caught in it and block 62 will be swung to one side ofits casing 48. This will release bumper or plunger 88 for engagementwith arm I I6 and said arm will be swung laterally out of its Figv 6position. Flat end portion I22a will thereby be caused to engage leversI52 and an electric circuit will there by be closed in order to actuatethe stop-motion mechanism of the knitting machine. The operator of themachine may now swing arm II 8 a full 180 from its Fig. 6 position untilball I3 seats itself in recess I42. This outward position of arm I I3provides two advantages: In the first place, it serves notice of adefect in the knitted fabric which must be cleared before the machine isset back into operation. In the second place, it prevents the holedetecting mechanism from knocking-off the machine before the operator ofthe machine has an opportunity to clear the knitted fabric. The reasonfor this is plain: when arm II 3 is disposed diametrically opposite itsFig. 6 position, fiber pads I44 will prevent contact between fiattenedend portion I22a of shaft I22 and contact leaves I52. When the fabric iscleared, arm H8 is returned to its Fig. 6 position and it is once againready for engagement with bumper or plunger 88 when another defect inthe fabric is detected.

Fig. 6B shows a modified form of the hole detecting mechanism last abovedescribed, the modification being principally in its switch mechanismrather than in the hole detecting mechanism. It will be noted that ablock I63 of insulating material is secured to casing I6 and a leaf typeof contact member I62 is secured at one end to said block. The oppositeend projects forwardly of crossbar 98 and it will be noted that theintermediate portion of said leaf is bowed to avoid contact with saidcrossbar when the latter is in its retracted position. When a hole isdetected in the knitted fabric, the process above described will takeplace and the bumper or plunger will be thrust forwardly against theknitted fabric. The crossbar will, of course, move together with thebumper or plunger and it will then engage the free end of leaf I62. Thiswill close the circuit to the stop motion mechanism, thereby stoppingthe knitting machine.

In this form of the invention, there is no need for arm I I8 and for theswitch mechanism which said arm controls. Instead, a conductor I64 isconnected to contact leaf I62 and said conductor I64 projects up throughthe hollow shaft I66 of the knitting machine. It is then connected tothe stop-motion mechanism in the usual manner. The sole difference, tothe extent that concerns the present invention, between the knittingmachine of Fig. 6B and the knitting machine of Fig. 1, is the differencebetween solid shaft I4 and hollow shaft I66. It is patently impossibleto draw a wire up through the solid shaft and it is therefore necessaryto provide a switch mechanism on the outside of the knitted tube. Insome of the more modern knitting machines, the central shaft is hollowand it is therefore possible to connect the hole detecting mechanism tothe stop motion mechanism by means of a conductor drawn through thehollow shaft. The bumper or plunger 88 is used in this form of theinvention only for the purpose of resetting the hole detecting mechanismfrom outside the knit ted fabric. It is not used to actuate a switchmechanism located outside the knitted fabric.

Turning now to the second form of this invention and to Figs. 7, 8', 9and 10, it will be seen that a hole detector 200 is provided on theoutside of knitted tube 202. This hole detector includes a casing 264which has a block 266 connected to its back wall. A bracket 208 projectsinto a hole in block 266 and supports said block and said casing. Itwill be noted that this hole, designated 2H1 in the drawing, extendsvertically of block 266 and a vertical portion 2 I2 of bracket 268projects into said hole. It is therefore possible to swing casing 204about said vertical portion 2I2 of the bracket to any desired position.A set screw 2 I 4 or a pair of set screws are screwed into block 206 forengagement with said vertical portion 2I2 of the bracket to hold thecasing in any desired position thereon.

Pivotally and slidably mounted in casing 204 is a block 2I6 whichcorresponds to block 62 of the first form of this invention. Morespecifically, block 2 I6 has a pair of pins 2 I 8 projecting outwardlytherefrom on a common axis. These pins project through registering slots226 which are formed in the top and bottom walls 222 of the casing.Since pins 2 I8 are mounted in slots 226 it is possible for block 2 I6to engage both in pivotal and slidable movement in the casing. Springs224 are provided adjacent walls 222 of the casing and oneend of saidsprings is secured to said walls by means of pins or rivets 226 and theopposite end of said springs is secured to pins 218. These springs arethereby enabled to act upon block 2 l 6 and to urge it forwardly in thedirection of the knitted tube 262. The back wall 228 of the casing isprovided at its front end with. a pair of clips 239 which project infront of block 2E6 when said block is in its retracted position in thecasing. The forward end of said block is provided with a pair of bosses232 which are engageable with clips 230 to hold the block in retractedposition in the casing. Springs 224 tend to hold said block 2l6 in itsforwardmost position, that is, with its bosses 232 in tensionedengagement with clips 230 of the casing. This arrangement of parts issimilar to the arrangement of parts of the first form of this inventionabove described.

A plurality of holes 234 is formed in block 2 Hi, longitudinallythereof, and in spaced, parallel relationship to each other. Fixed insaid holes are tubes 236 which are held in place therein by means of setscrews 238. The forward ends of said tubes are provided with caps 24!)and said caps have slots 242 formed therein to accommodate probes orfeelers 244. These probes or feelers have reduced forward ends for readypenetration into holes or other similar defects in the knitted fabric.Springs (not shown) are provided in tubes 236 for engagement with probesor feelers 244 to urge them resiliently forwardly.

It will be noted in Fig. 9 that when the probes or feelers are inscanning engagement with the outside of the knitted tube, they assumestaggered or offset positions relative to each other in order to adaptthemselves to the taper of the knitted tube. When a hole is encounteredby any one of these probes or feelers, its reduced forward end projectsinto said hole as Fig. '7 clearly shows. In the knitting machine, underdiscussion, the knitted tube rotates and the hole detector is maintainedin a stationary position. Hence, when one of the probes or feelersenters a hole in the knitted tube, and said tube rotates in thedirection of arrow 246, the effect will be to swing block 2 I 6 out ofits casing to its dotted line position shown in Fig. '7. When this takesplace, the switch mechanism 248 on casing 204 is actuated and theknitting machine caused to stop. The switch mechanism will now bedescribed.

A switch box 250, made of electrically non-conductive material, issecured to the outside of wall 228 of the casing by means of screws 252and 254. Mounted within the switch box is a pair of leaf springs 256which are secured to a pair of bind ing posts 258. These leaf springsserve as electrical contact members with respect to a slidable contactmember 260. This slidable contact member has a longitudinal portionwhich is slidably mounted in a channel 262 formed in wall 228 of thecasing. It has a pair of sidewardly extending fingers 264 at its backend and a lug 266 at its forward end, projecting in the oppositedirection from fingers 254. It will be noted that when the slidablecontact member 260 moves backwardly, its fingers engage leaf springs256, thereby closing the circuit which will hereinafter be described.Its lug 266 is engageable with the forward end of block 2H6 and when theblock is in retracted position within the casing, said block preventsthe slidable contact member from moving backwardly into engagement withthe two 12 leaf springs 255. When block 215 is pulled outwardly from itscasing to its dotted line position in Fig. '7, it disengages lug 266 andthereby frees the slidable contact member for backward movement intoengagement with the leaf springs.

This backward movement of the slidable contact member takes place underthe influence of a tension spring 268. The forward end of said spring isconnected to the slidable contact member by means of a pin or stud 212.This stud projects through a slot 222 formed in channel portion 262 ofthe back wall 228 of the casing and it is movable forwardly andbackwardly through said slot. The back end of the spring is secured tosaid back wall of the casing by means of a. pin or stud 216. Hence, whena hole is encountered in the fabric and block 296 is pulled out ofengagement with lug 265, said slidable contact member is pulledbackwardly into contact with the two leaf springs 256.

It will be noted that spring 268 acts against springs 22 abovementioned. Spr ngs 224 tend to urge block 2H5 forwardly and spring 268acts to pull the slidable contact member 262, and with it said block2V6, backwardly. The two springs 224 are, however, stronger than. spring258 and hence they prevail as. long as block 2 it and lug 265 are inengagement with each other. When the block disengages the lug, spring 2%is free to pull the slidable contact member into engagement with leafsprings 256. It will be noted that a pair of pins 218 are fixed to theswitch box 250 for engagement with leaf springs 256. These pins tend toprevent the leaf springs from engaging the slidable contact memberprematurely.

The resetting mechanism for resetting both block 2 I 6 and the switchmechanism is manually operable by means of a knob 213 which is slidablymovable on a bar 28!! which is secured to block 206 of the casing. Awire 282 is secured at its back end to knob 218 by means of a set screw284. The forward end of said wire is looped around a second wire 286-which is secured to the back end of block 2H2. When knob 27B is pulledbackwardly on bar 282, its wire 282 pulls upon block 2 l G and draws itbackwardly into the casing. It will be understood that the backwardmovement of block 2H5 is from its dotted line position in Fig. 7. Sincewire 2% is offset from the axial center of block 2H5, the backward pullon said block through said wire has the effect of swinging it back fromits angular position indicated by the dotted lines in Fig. 7 to itslongitudinally aligned position shown in Figs. 8 and 10 This brings theforward end of block 2H5 into renewed engagement with lug 265 of theslidable contact member and when the knob is released, springs 224 willreturn block 216 to its forwardly extending position and by the sametoken slidable contact member 252 will also be thrust forward until itsfingers 262 are out of engagement with leaf springs 256. The circuit isnow open.

A bumper is provided to prevent the knob from being pulled backwardlybeyond a predetermined point. This bumper comprises a plate 238 on backwall 228 of the casing, a laterally bent end piece 299 on said plate, adog 292 which is secured to wire 232, still another wire 2% secured tosaid dog and a compression spring 295 which is mounted on wire 2%. Dog222 projects through a slot 228 in the back wall 228 of the casing and aregistering slot 320 which is formed in plate 288. When knob 218 isretracted on bar 280, the ends of spring 296 are brought into abut: mentwith dog 232 and end piece 290. The move- 13 ment of said dog towardsaid end piece will be limited by spring 296 and so will the backwardmovement of knob 218, wire 232 and block 2 [6.

End piece 291! and its plate 288 also perform another extremelyimportant function. When a long run of defective material is encounteredand the knitting machine is stopped as soon as the first hole isdetected, it becomes necessary to run the machine until the fabricclears without interference on the part of the hole-detecting mechanism.This can be effected by simply pushing end piece 2% forwardly until theslidable contact member 260 disengages the fixed contact members 256.The machine may now be run without interruption until the fabric clears.Knob 218 may then be pulled backwardly to reset both the hole-detectingmechanism and the switch mechanism. Both will be reset simultaneouslyand without any danger of the operator of the machine resetting the onewhile forgetting to reset the other.

Fig. 11 shows an electrical diagram of the electrical system controlledby the hole-detect ing mechanism herein. described and claimed. In thediagram, reference characters 3M and 3% represent conventionalstop-motion devices of a conventional circular knitting machine. Thereference character 3M represents a hole-detect ing device made inaccordance with this invention. It will be noted that the high side of atransformer 306 is connected by conductors 308 and 3H) to a suitablesource of alternating electric current. Conductors 3l2 and 3M areconnected to the low side of the transformer. It will be noted thatconductor SM is connected by means of conductors 3 i t, 35 8 and 321)respectively to stop-motion devices 300 and 392 and hole-detector 304.Reference character 322 indicates the ground connection of hole-detector3M. A sec=- ond conductor 324 is connected to hole-detector 3534 and toone side of a signal bulb 326. Another conductor 328 is connected to theopposite side of the bulb and it is also connected, together withconductor M2, to a controller 336. A slidably mounted rod 332 iscontrolled by said controller and said rod is connected. in conventionalmanner to the clutch of the knitting machine so that movement of saidrod in one direction stops the machine and movement in the opposidedirection frees the machine for further operation.

The controller is conventional and its rod 332 is spring-urged formovement in the direction which enables it to stop the machine. When oneof the probes of hole-detector 3% is caught in a hole in the knittedfabric, one of the above described switches mechanisms (for exampleswitch members 256 and 260 in Figs. 9 and 10) which is connected to saidhole-detector closes and grounds the unit. The circuit to the controlleris thereby closed through the ground and an electro-magnet (not shown)in the controller actuates a release mechanism which releases rod 332for spring-urged movement in the direction required for stopping themachine. A switch (not shown) in the controller is also actuated whenthe electro-magnet is energized and the controller circuit through theground is thereby broken. The signal light is now energized and itflashes to call the attention of the operator of the machine to the factthat the fabric is defective and the machine is stopped.

Fig. 12 shows a variation in construction of the double ring guide whichengages the knitted tube and holds it taut for the hole-detecting proce-1d dure. The double ring guide first above described has an upper and alower ring member which are offset from each other to conform to thecurvature or taper of the knitted tube. It is possible to conform thedouble ring guide to the knitted tube without offsetting the two ringmembers from each other and this is shown in Fig. 12. It will there beseen that a double ring guide'is provided which has an upper ring member408, a lower ring member 402, a pair of end blocks 466 to which the endof said ring members are secured and a vertical bar 404 which extendsfrom the upper ring member 400 to the lower ring member 402 at theforward or operative edges of said ring members. These forward oroperative edges register with each other since the upper and lower ringmembers are not offset from each other in any respect whatsoever.

Rods 4% correspond to rods 32 and 33 of the first form of thisinvention. At their back ends they are supported by a bracket such asbracket I 6. At their forward ends they are provided with enlargedcircular portions M0 which are provided with centered holes toaccommodate bolts H2. enlargements 4W of rods 408. It is possible byloosening these bolts to swivel or pivot blocks 406 about the axis ofsaid bolts. Since the two ring members 400 and 402 are secured to blocks406, the effect is to cause them as well as said blocks to pivot aboutbolts H 2. This pivoting movement enables the double ring guide toconform to the curvature or taper of the knitted tube i2 as Fig. 12clearly shows. In other words, the double ring guide shown in Fig. 12 isadjustable to the taper or curvature of the knitted tube, whatever thattaper or curvature may be.

The foregoing is illustrative of preferred forms of this invention. Itwill be understood and appreciated that these preferred forms may bemodified and other forms may be provided within the broad spirit of theinvention and the broad scope of the claims.

I claim:

1. In a hole-detecting mechanism for detecting holes in the knitted tubewhich is produced on a circular knitting machine, a double guide whichengages the inside of the knitted tube, said guide having an upperhorizontally extending guide member and a lower horizontally extendingguide member, said guide members being vertically spaced from each otherand having arcuate edges which engage the knitted tube and hold thatportion of the knitted tube which is disposed between said guide memberstaut, and a plurality of spring-urged probes which engage the tautportion of the knitted tube in the area between said guide members.

2. In a hole detecting mechanism, the combination set forth in claim 1,wherein the upper and lower guide members are oiTset from each other tocorrespond to the taper of the knitted tube.

3. In a hole detecting mechanism, the combination set forth in claim 1,wherein the upper and lower guide members are offset from each other tocorrespond to the taper of the knitted tube, a vertically extendingguide bar being secured to said upper and lower guide members and beingdisposed at an inclined angle from the arcuate edge of the lower guidemember to the arcuate edge of the upper guide member to conform to thetaper of the knitted tube.

4. In a hole detecting mechanism, the combination set forth in claim 1,wherein the spring- These bolts secure blocks 406 to circularv urgedprobes are supported by and between the upper and lower guide members ofthe double:

guide.

5. In a hole detecting mechanism, the combination set forth in claim 1,wherein the double guide is adjustably positioned within the knittedtube for engagement with said tube irrespective of. the diameter of saidtube.

6. In a hole detecting mechanism, the combination set forth in claim 1,wherein the double guide is mounted on the inside of the knitted tubeand the spring urged probes are mounted on the outside of the knittedtube.

7. In a hole detecting mechanism, the combination set forth in claim 1,wherein the double guide and the spring-urged probes are all mountedWithin the knitted tube and wherein there is relative movement betweenthe probes and the knitted tube, a pivotally mounted block beingprovided for carrying said probes, said block being caused to pivot whenone of said probes is caught in a hole in the knitted tube, aspring-urgedplunger supported adjacent said block for forward movementinto engagement with the knitted tube in response to its spring actionand for backward movement out of engagement with said knitted tubeagainst said spring action, a catch which engages said plunger andprevents it from moving forwardly into engagement with the knitted tubeand a trigger mechanism which is engageable with said catch to releasethe catch and thereby free the plunger for forward movement intoengagement with the knitted tube in response to its spring action, saidtrigger being actuated by the pivotally mounted block so as to releasethe catch and free the plunger when the block engages in pivotalmovement.

8. In a hole detecting mechanism, for circular knitting machines, ablock which is pivotally mounted within the knitted tube produced onsaid machines, a plurality of spring-urged probes on said block,relative movement between the knitted tube and the probes beingprovided, said probes being maintained by said block in engagement withsaid knitted tube, whereby the block is caused to pivot when any one ofsaid probes is caught in a hole in the knitted tube, a springurgedplunger mounted adjacent said block for forward movement under itsspring action into engagement with the knitted tube to form a bulgetherein and for backward movement in opposition to its sprng action todisengage said knitted tube, a spring-urged catch which holds theplunger in retracted position out of engagement with the knitted tube, atrigger on said block which is pivotally engageable with said catch torelease said catch and thereby to free the plunger for forward movementinto engagement-with the knitted tube when a probe is caught in a holein the knitted tube and the block is thereby caused to pivot, an armpivotally mounted outside of the knitted tube for engagement with theplunger when said plunger engages the knitted tube and forms a bulgetherein, a switch mechanism connected to said arm and a stop-motiondevice controlled by said switch mechanism, whereby engagement of the punger with said arm causes the arm to pivot and the switch mechanism toclose, thereby actuating the stop-motion device.

9. In a hole detecting mechanism, the combination of claim 8, wherein adouble ring guide is mounted within the knitted tube and in engagementtherewith, one of the rings of said guide being disposed above theprobes and the other being disposed below the probes and supportingtheblock between them for pivotal movement. relative to them, wherebythe knitted tube is held in taut condition between the two rings of saidguide to enable the probes to engage in smooth and precise scanning ofthe knitted tube.

10. In a hole detecting mechanism, the com bination of claim 8, whereinthe back end of the plunger is engageable-with the trigger on the bloc-kwhen the block is in pivoted position and the plunger is movedbackwardly, whereby the block is returned to its original non-pivotedposition.

11. In a hole detecting mechanism, the combination of claim 8, whereinthe switch mechanism comprises a shaft to which the arm is secured andwhich is rotatably mounted for rotary movement on its longitudinal axis,one end of said shaft being flattened on at least one side thereof andinsulated on said flattened side, anda contact member which is mountedfor engagement with said insulated, side of the shaft when said shaft isin one angular position and which is engageable with a non-insulatedpart of said shaft when the shaft is turned to another angular position.

12. In a hole detecting mechanism, the combination of claim 8, whereinthe switch mechanism comprises a shaft to which the armis-secured andwhich is rotatably mounted for rotary movement on its longitudinal axis,one end ofsaid shaft be-- ing flattened on diametrically opposite sidesand being insulated on said flattened sides, and a pairof contactmembers which are mounted for engagement with said insulated sides ofthe shaft when said shaft is in one angular position and,

which are engageable with non-insulated parts of said shaft when theshaft is turned to anotherangular position.

13. In a hole detecting mechanism, a switch mechanism comprising abracket, a shaft mounted. in said bracket for rotary movement on itslongitudinal axis, an arm secured to said shaft and.

extending laterally thereof to control the angular position of saidshaft in said bracket, one of the ends of said shaft being flattened andinsulated. on both sides, and a pair of spring contact mem-- bers whichare supported at one end by said bracket and which are insulated fromsaid bracket, the opposite ends of said spring contact, members beingengageable with the insulated sides of the shaft when the shaft is inone angular position in said bracket and also when the shaft is inanother angular position in said bracket,

removed from the first position, and which are engageable withnon-insulated parts of the shaft, when the shaft is turned to any otherangular position.

14. In a hole detecting mechanism, the-combination of claim 13, whereinthe shaft is provided with a pair of recesses formed therein ondiametrically opposite sides, a spring-urged ball being mounted withinthe bracket for engagement with said recesses to resiliently hold theshaft in the first mentioned position and in the position which is 180removed therefrom.

References Cited in the file. of this patent UNITED STATES PATENTS-Number Name Date 1,081,410 shimer Dec. 16, 1913 2,259,607 Berthold' Oct.21, 1941 2,570,995 Vossen Oct. 9, 1951 2,571,211 Crawford Oct. 16, 1951

